Study	Sample size	Proportion (%)	95% CI	Weight (%)	Test for heterogeneity
				Random	Q	69.3607
Goshima et al 2004	318	90.811	87.166 to 93.807	32.82	DF	2
Taylor et al 2007	841	72.057	68.891 to 75.067	33.78	Significance level	P < 0.0001
Abou-Zamzam et al 1997	513	85.185	81.811 to 88.147	33.40	I2 (inconsistency)	97.12%
Total (random effects)	1672	83.229	70.999 to 92.617	100.00	95% CI for I2	94.24 to 98.56